giles
e80e655b51
In `resume_vm`'s `restore_reuse`, the saved sp captured by `call_closure_reuse` was ignored when restoring the caller frame after the async callback finished. The suspended callee's locals/temps stayed on the value stack above saved_sp, so subsequent LOCAL_GET/SET in the caller frame (e.g. letrec sibling bindings waiting on the suspending call) read stale callee data instead of their own slots. Sibling bindings appeared nil after a perform/resume cycle on the JIT path used by the WASM browser kernel. Fix: after popping the callback result and restoring saved_frames, reset `vm.sp <- saved_sp` (when sp is above), then push the callback result. Mirrors the OP_RETURN+sp-reset discipline that sync `call_closure_reuse` already follows. New tests in `spec/tests/test-letrec-resume.sx` cover single binding, sibling bindings, mutual recursion siblings, and nested letrec — all four pass. Full OCaml run_tests: 4529/5868 (was 4525/5864), zero regressions. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
45 lines
2.1 KiB
Plaintext
45 lines
2.1 KiB
Plaintext
;; Letrec + perform/resume regression tests — Step 2
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;; Verifies sibling bindings survive across an IO suspension when the
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;; suspended call goes through call_closure_reuse (JIT path).
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;; The browser/WASM kernel reuses the host VM via call_closure_reuse;
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;; if restore_reuse drops the caller's saved sp, sibling letrec bindings
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;; come back as nil after resume.
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(defsuite
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"letrec-resume"
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(deftest
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"single binding survives perform/resume"
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(let
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((state (cek-step-loop (make-cek-state (quote (letrec ((f (fn () (perform {:op "io"})))) (f))) (make-env) (list)))))
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(assert (cek-suspended? state))
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(let
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((final (cek-resume state 7)))
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(assert (cek-terminal? final))
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(assert= (cek-value final) 7))))
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(deftest
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"sibling bindings survive perform/resume"
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(let
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((state (cek-step-loop (make-cek-state (quote (letrec ((g (fn () 100)) (f (fn () (perform {:op "io"})))) (+ (f) (g)))) (make-env) (list)))))
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(assert (cek-suspended? state))
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(let
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((final (cek-resume state 5)))
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(assert (cek-terminal? final))
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(assert= (cek-value final) 105))))
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(deftest
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"mutual recursion sibling preserved across resume"
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(let
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((state (cek-step-loop (make-cek-state (quote (letrec ((even? (fn (n) (if (= n 0) true (odd? (- n 1))))) (odd? (fn (n) (if (= n 0) false (even? (- n 1))))) (fetch (fn () (perform {:op "io"})))) (let ((x (fetch))) (even? x)))) (make-env) (list)))))
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(assert (cek-suspended? state))
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(let
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((final (cek-resume state 4)))
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(assert (cek-terminal? final))
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(assert= (cek-value final) true))))
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(deftest
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"nested letrec — outer sibling survives inner perform"
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(let
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((state (cek-step-loop (make-cek-state (quote (letrec ((outer-val (fn () 99)) (inner-call (fn () (letrec ((suspend-fn (fn () (perform {:op "io"})))) (suspend-fn))))) (+ (inner-call) (outer-val)))) (make-env) (list)))))
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(assert (cek-suspended? state))
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(let
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((final (cek-resume state 1)))
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(assert (cek-terminal? final))
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(assert= (cek-value final) 100)))))
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